This invention relates to an elongated lightweight fiber reinforced composite resin pultrusion-formed piece in which a layer of a fiber reinforced resin is formed on a surface of an elongated honeycomb structure, and also to a method of manufacturing this type of formed piece.
An elongated lightweight fiber reinforced composite resin pultrusion-formed piece in accordance with the present invention is formed as an elongated member having a rectangular sectional shape, is capable of suitably resisting a bending force as well as axial tensile and compressive forces, and can be used as, for example, frame members and mechanical parts in the fields of aircraft, outer space, motor vehicles, ships and railroads, as structural framework members such as pillars in the fields of civil engineering work and architecture, or as light structural members in other various fields.
Elongated light structural members are in demand in these various fields. Conventionally, fiber reinforced composite members having reinforcing fibers such as carbon fibers or glass fibers have been proposed as this type of structural member. A composite member is formed into a shape of a pipe for a reduction in the overall weight. For a further reduction in the weight, the pipe tends to be reduced in thickness. If the thickness of the pipe is reduced, the bending strength and the compressive strength (buckling resistance) in a direction perpendicular to the axial direction are reduced. There is therefore a limit of the reduction in the thickness. In particular, in the case of pultrusion, the problem of occurrence of damage to the formed piece in a mold and in an extracting unit is encountered, and it is therefore difficult to form the desired product by pultrusion.
The inventors of the present invention have found that an elongated lightweight fiber reinforced composite resin pultrusion-formed piece improved in bending strength and compressive strength in a direction perpendicular to the axial direction (buckling resistance) as well as in tensile strength and compressive strength in the axial direction can be realized by forming a thin fiber reinforced resin layer on the outside surface of an elongated light reinforcing member constituted by an elongated honeycomb structure body formed of paper, a plastic or a light metal, and that this type of formed piece can be suitably manufactured by the ordinary pultrusion method.
Such an elongated honeycomb structure body can serve as a mandrel when the formed piece is manufactured by the pultrusion method, thereby eliminating the need for separately providing a mandrel while ensuring that the formed piece can be manufactured at a high speed with improved efficiency and without any damage.
The present invention has been achieved on the basis of this finding.